﻿using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Text;
using System.Text.RegularExpressions;
using System.Threading.Tasks;
using System.Web;

namespace Pay.Core {
    /// <summary>
    /// Ip
    /// </summary>
    public class IPHelper {
        /// <summary> 
        /// 取得客户端真实IP。如果有代理则取第一个非内网地址 
        /// </summary> 
        public static string IPAddress {
            get {
                string result = String.Empty;

                result = HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"];
                if (!string.IsNullOrEmpty(result)) {
                    //可能有代理 
                    if (result.IndexOf(".") == -1)    //没有“.”肯定是非IPv4格式 
                        result = null;
                    else {
                        if (result.IndexOf(",") != -1) {
                            //有“,”，估计多个代理。取第一个不是内网的IP。 
                            result = result.Replace(" ", "").Replace("'", "");
                            string[] temparyip = result.Split(",;".ToCharArray());
                            for (int i = 0; i < temparyip.Length; i++) {
                                if (IsIPAddress(temparyip[i])
                                    && temparyip[i].Substring(0, 3) != "10."
                                    && temparyip[i].Substring(0, 7) != "192.168"
                                    && temparyip[i].Substring(0, 7) != "172.16.") {
                                    return temparyip[i];    //找到不是内网的地址 
                                }
                            }
                        } else if (IsIPAddress(result)) //代理即是IP格式 
                            return result;
                        else
                            result = null;    //代理中的内容 非IP，取IP 
                    }
                }

                string IpAddress = (HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"] != null && HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"] != String.Empty) ? HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"] : HttpContext.Current.Request.ServerVariables["REMOTE_ADDR"];

                if (string.IsNullOrEmpty(result))
                    result = HttpContext.Current.Request.ServerVariables["REMOTE_ADDR"];
                if (string.IsNullOrEmpty(result))
                    result = HttpContext.Current.Request.UserHostAddress;
                if (string.IsNullOrEmpty(result) || result == "127.0.0.1") {
                    IPAddress[] arrIP = Dns.GetHostAddresses(Dns.GetHostName());
                    result = arrIP.Where(s => s.AddressFamily == System.Net.Sockets.AddressFamily.InterNetwork).FirstOrDefault().ToString();
                }
                return result;
            }
        }

        //// <summary>
        /// 判断是否是IP地址格式 0.0.0.0
        /// </summary>
        /// <param name="str1">待判断的IP地址</param>
        /// <returns>true or false</returns>
        public static bool IsIPAddress(string str1) {
            if (str1 == null || str1 == string.Empty || str1.Length < 7 || str1.Length > 15) return false;
            string regformat = @"^\d{1,3}[\.]\d{1,3}[\.]\d{1,3}[\.]\d{1,3}$";
            Regex regex = new Regex(regformat, RegexOptions.IgnoreCase);
            return regex.IsMatch(str1);
        }
        public static long IpToInt(string ip) {
            if (!IsIPAddress(ip)) return 0;
            char[] separator = new char[] { '.' };
            string[] items = ip.Split(separator);
            return long.Parse(items[0]) << 24
                    | long.Parse(items[1]) << 16
                    | long.Parse(items[2]) << 8
                    | long.Parse(items[3]);
        }
        public static string IntToIp(long ipInt) {
            StringBuilder sb = new StringBuilder();
            sb.Append((ipInt >> 24) & 0xFF).Append(".");
            sb.Append((ipInt >> 16) & 0xFF).Append(".");
            sb.Append((ipInt >> 8) & 0xFF).Append(".");
            sb.Append(ipInt & 0xFF);
            return sb.ToString();
        }
    }
}
